The small size of features patterned using extreme ultraviolet (EUV) light radiation means that any particulate contamination within a lithographic apparatus can have significant detrimental effects on a manufactured integrated circuit. For example, if a particle was present on a patterning device during patterning it may cause an image of the particle to be formed on a substrate. It is known to use a pellicle film to protect a patterning device from particle contamination, so as to prevent any degradation in the performance of the lithographic apparatus in the presence of some particles. However, to form a pellicle film which is sufficiently transparent to EUV radiation so as to not reduce the performance of the lithographic apparatus each pellicle film must be made of an extremely thin film. The extremely thin film also requires having high degree of chemical stability with respect to EUV light.